Spring for timepieces.



W. VON BOLTON. SPRING PoR 'TIMEPIEOBS.

APPLICATION IILED NMBS, 1907.

947,146. I y Patented Ja1L18,191o.

gn/ue nto@ Mrnu von Bglf", @tm

2 0 strength, resistancelto li tofore utilized,

50 tage over .steel of hein oisrrEDj-srAf WERNER VON BOLTON, or CHARHALSKE, A. IGf., OF BERLIN,

"r'rnNBUnG, GERMAN GERMANY, A CORPORATION or GERMANY.

Y, ASSIGNOR TO SIEMENS SPRING NE012,- TIMEPIECES.

.Specilcation Ot Letters Patent.

Patented Jan. 1s, 1910.

Original application Med February 17, 1905, Serial No. 24g-6,189.Divided and this application l'ed Inno 8,

1907. .Serfa11 o. 378,023.

To all whom it may concern: i

Be it known that I, Vinnisnn von Bonrox,

a subject of the Czar of Russia, and resident of Charlottenburg, nearBerlin, Germany,

5 have invented certain new and useful Imor `Timepieces, of

` provements in Springs which the following is a specification.

' My present application is va division of my prior application, filedFebruary 17, 1905,

serially numbered 246,189.

The present invention relates to an iinproved construction of springs,vand more particularly to springs which are employed 1n tiine pieces. A

Htretotore springs of this character have generally been made of steel,due to the fact that that niaterialcombines a great'niany advantageousproperties, such as bein ca able of easy manufacture, consi era le wear,and the like There are, however, certainv inherent objections to the useof steel in springs for time pieces. rlheinaterial is not permanent un--der all conditions, and, being susceptible to magnetism, rusting, andwear, itfproves unsatisfactory. Before my invention, however, so far asI ani aware, no efficient substitute for st e1 'was suggested, and Itheretore believe hat I am the first to overcome these difficulties andto provide a spring for time pieces which is capable of answering the,severe rctlriirei'nents which are demand-v ed. In accordance withmyinvention, I forni tie spring of tantalum. Tantaluni has been proposed.foruse in filaments for wherein itsA high melting point is thc chiefproperty utilized. I have found, however, that tantalum possesses agreat many properties which were not herel and which are of peculiaradvantage in the s rings ot time pieces. It possesses, like stee theproperty of being easily worked and hardened. It Offers greate:`resistance to `fracture than steel,

elect rie lighting,

` and has great resilience and elasticity.

Its hardness can be increased to such a degree as to greatly exceed thatof. the best steel and to be almost equal to the diamond in thisrespect. It has`the 'further advanone of the precious metals which isnot al ecte'd by the atmosphere, and which, at ordinary temperatures,completely resists the action of most acids.

A further advanta e which it possesses is that it is substantie lynon-magnetic. Being extremely hard, it offers great resistance to at thesame time possessing great strength, it has the yielding property 0fsteel with less liability of fracture. Bein non-inagnetic'and resistanttoacids an to the at mos'phere, it has a ermanence which steel entirelylacks.- Having a very highmelting point, it is capable of use attemperatures eyond which steel would be of service.

I have illustrated in the accompanying drawing a clockl spring composedof tantalum. Y

In order to work the metal satisfactorily,

electrical current through it. By the fusing process the metal is treedfrom impurities, while at the saine time being rendered homogeneous. Themetal which has been fused, and thus rendered homogeneous, can bereadily worked mechanicallyin any known nian- Aner. It can be hammered,rolled, drawn, filed and the like, and thus brought into any desiredform. lVlieiibeing worked mechanically, especially if it contains asmall quantity of carbon or other hardening medium, the metal readilyassumes so great a degree of hardness that further working is renderedimpossible and it must 'then be carefully soft again. In vthis annealingprocess care inust be. taken that the temperature does not risc toohigh, as otherwise the metal is more easily attacked by the oxygen ofthe atinospliere. Even iii the form ot' the finest drawn wires, or thethinnest rolled bands, however, the metal will stand a heating in theOpen air u lto a dark redheat without being a preciably affected. Whenso heated tile mctalshows a colorizatioii similar to tem pered steel.AIn order to prevent too great a heat, particularly of fine parts ofpure tantaluin, it is pre erable to effect the heat- 2 ing 'indirectlyby bringing large plates or drums to thetemperature to which the parts lto be heated-. are required to be brought i and then to bring theobjects of4 tantaluni to l be heated iii contact. with these plates oriti/mustbe reviously well fused. This is. prrtbly one by heating themetal in a vacuum b electrical means, such as by electricalv resistanceor directly by passing an' `Wear, and, being resilient andv elastic,while heated o'r annealed in Order to be rendered drums. -If, onthegther `h-a'nd, it'is desired tu raise the ob'ects^ of *tantalumto'higher temperatures wlthout their Abein materxallfy u'ected Qnthersur'fg'vcegg itis a vantageous vto effect the heatmg 1n algvalcuum, asat Avery -high temperatures pure' tantalum clombnes "i II clai-m: I Aspring for tmepieces composed of substantially pure tantalum.

WERNER VON B0LT0N.' I Witnesses:

WOLDEMAR HAUPT, HENRY HASPER.

